AP Environmental Science Indoor Air Pollution (Chapter 16)

Sources of Indoor Air Pollution Sources of indoor air pollution can come from both human activities and natural processes Two of the most common household pollutants are dust mites and pollen Sources of Indoor Air Pollution

Sources of Indoor Air Pollution Environmental Tobacco Smoke (secondhand smoke) Emitted by smoke exhalation and burning tobacco products Contains thousands of toxic chemicals (Nitrogen oxides, Carbon monoxide, Hydrogen Cyanide) Causes health issues mainly in the respiratory system Exposure varies with amount of tobacco smoke present, size of the space, and ventilation Sources of Indoor Air Pollution

Sources of Indoor Air Pollution Carbon Monoxide Colorless, odorless gas Common sources include gas stoves, space heaters, leaky chimneys, exhaust from attached garage spaces, environmental tobacco smoke Health effects range with concentration. Low concentrations can lead to fatigue, dizziness, and nausea. High concentrations can be fatal. Proper ventilation and maintenance of appliances are the best ways to reduce exposure to high concentrations of CO Sources of Indoor Air Pollution

Sources of Indoor Air Pollution Radon Gas Naturally occurring radioactive gas that is colorless, odorless, and tasteless Comes from the radioactive decay of radiogenic uranium to stable lead Enters homes through rock or soil that contains concentrations of uranium Sources of Indoor Air Pollution

Sources of Indoor Air Pollution Radon gas enters homes and buildings in 3 main ways: Migration through soil and rock into basements and lower floors Dissolution in groundwater pumped into wells Radon-contaminated materials used in construction Sources of Indoor Air Pollution Home radon testing and mitigation video

Sources of Indoor Air Pollution Asbestos Fibrous mineral fragments used in building materials Common sources include roof shingles, ceiling and floor tiles, insulation, and fire retardant fabrics Health risks come from inhalation of fibers when building materials are broken up. Asbestos fibers attach to respiratory tissue and may develop tumors in the lungs National policies have restricted the use of asbestos in building materials since 1969 Sources of Indoor Air Pollution

Sources of Indoor Air Pollution Formaldehyde Volatile organic compound often used as a preservative or coating material in building supplies Common sources include dry wall coating, wood flooring, new furniture Health risks from low exposure include skin, eye, nose, and throat irritation. At greater exposure formaldehyde may cause cancer. Sources of Indoor Air Pollution

Sources of Indoor Air Pollution Additional pollution sources include: Legionella pneumophila- bacterium that grows in stagnant water and can be transported through the air Mold Pesticides (ex: methyl bromide) Chloroform (chlorine treated water heated above 105oF) Para-dichlorobenzene (moth balls) Flame retardants Sources of Indoor Air Pollution

Sources of Indoor Air Pollution Indoor air pollution is often highly concentrated compared to outdoor pollution because of the numerous sources of pollution, proximity to the sources, and lack of ventilation Sources of Indoor Air Pollution

Sources of Indoor Air Pollution Newer homes are often more susceptible to indoor air pollution issues than older homes for various reasons: Energy efficient windows and doorways seal in air and prevent circulation New construction materials are more likely to contain chemicals that could be emitted into indoor air spaces New homes are more likely to be built on slabs that increases chances of air pollution from the ground Sources of Indoor Air Pollution

Sources of Indoor Air Pollution Heating and air systems in a home are designed to regulate indoor temperatures and ventilate using outdoor air Along with temperature, humidity must be controlled to prevent mold and mildew growth Ventilation systems are not designed to reduce indoor air pollution, if not maintained properly these systems can be sources of pollution themselves Sources of Indoor Air Pollution

Sources of Indoor Air Pollution Movement of air within a building depends on pressure and temperature differentials Windward sides of buildings build up higher pressure s and leeward sides tend to have lower pressure Home with different temperature controls in different areas can create movement due to temperature differentials Leaky buildings have greater air movement Sources of Indoor Air Pollution

Sources of Indoor Air Pollution A chimney effect (stack effect) occurs when there is a temperature differential from indoor to outdoor environments As warm air rises to upper levels cooler air can be drawn in from outside to replace it Sources of Indoor Air Pollution

Susceptibility and Health Effects Susceptibility to health effects from indoor air pollution can vary according to genetic factors, lifestyle and age Older people, children, and individuals with impaired health are generally more sensitive to air pollution Susceptibility and Health Effects

Susceptibility and Health Effects Diseases related to air pollution include: Asthma-bronchial tubes tighten & narrow. Bronchitis-tubes swell & fill with mucus. They get narrow, so it is hard to inhale & exhale. Emphysema-air sacs lose elasticity so it is hard to inhale & exhale. Lung cancer-cancer cells grow rapidly, poisoning body. Susceptibility and Health Effects

Susceptibility and Health Effects Sick buildings Building related illnesses (BRI) are illnesses produced by a building with identifiable pollutant sources Sick building syndrome (SBS) results when several cases of illness from a building have been reported with no identified source Numerous factors can be attributed to sick buildings including stress and working conditions Video Resource Susceptibility and Health Effects

Air Pollution Control To improve household air: Open windows when possible Use an air cleaner with a HEPA (high- efficiency particle air) filter. Grow spider plants- they absorb many pollutants. Air Pollution Control

Use adjustable fresh air vents for work spaces Solutions Indoor Air Pollution Prevention Cover ceiling tiles & lining of AC ducts to prevent release of mineral fibers Use adjustable fresh air vents for work spaces Increase intake of outside air Ban smoking or limit it to well ventilated areas Change air more frequently Set stricter formaldehyde emissions standards for carpet, furniture, and building materials Circulate a building’s air through rooftop green houses Prevent radon infiltration Use exhaust hoods for stoves and appliances burning natural gas Use office machines in well ventilated areas Use less polluting substitutes for harmful cleaning agents, paints, and other products Install efficient chimneys for wood-burning stoves Cleanup or Dilution

What Can You Do? Indoor Air Pollution • Test for radon and formaldehyde inside your home and take corrective measures as needed. • Do not buy furniture and other products containing formaldehyde. • Remove your shoes before entering your house to reduce inputs of dust, lead, and pesticides. • Test your house or workplace for asbestos fiber levels and for any crumbling asbestos materials if it was built before 1980. • Don't live in a pre-1980 house without having its indoor air tested for asbestos and lead. • Do not store gasoline, solvents, or other volatile hazardous chemicals inside a home or attached garage. • If you smoke, do it outside or in a closed room vented to the outside. • Make sure that wood-burning stoves, fireplaces, and kerosene- and gas-burning heaters are properly installed, vented, and maintained. • Install carbon monoxide detectors in all sleeping areas.